The present invention relates to a brake system which is capable of controlling both brake slip and traction slip.
Systems are known wherein a separating valve is provided in the brake line between the master brake cylinder and the wheel brake. To reduce the pressure in the wheel brake, fluid is drawn out of the wheel brake by a pump into a high-pressure accumulator. The accumulated fluid under pressure is returned to the wheel brake for the purpose of renewed pressure build-up.
Further, systems are known wherein a reversible pump is arranged in the brake line, and depending on the direction in which the pump is delivering, the pressure in the wheel brake can be decreased or increased.
Systems are also known which perform brake slip control that also are used for preventing slipping of the wheels when starting to drive.
It is the object of the present invention to provide a brake system in which the master cylinder is separated from the brake circuit during a brake slip control in which, only one pump is required, operated both for brake slip control and traction slip control, and which is of a closed circuit type in order that braking pressure can still be built up in the brake circuit despite failure of a valve.
It is a further object to minimize the size of the high-pressure accumulator.